The invention relates to a novel binding agent that is used to bind functional materials that can be manufactured in the form of a solid block. The solid, water soluble or dispersible functional material is typically dispensed using a spray-on dispenser which dissolves the solid block creating an aqueous concentrate of the functional material at a useful concentration. The aqueous concentrate is directed to a use locus. The term xe2x80x9cfunctional materialxe2x80x9d refers to a warewashing or laundry detergent or other active compound or material that when dissolved or dispersed in an aqueous phase can provide a beneficial property to the aqueous material when used in a use locus.
The use of solidification technology and solid block detergents in institutional and industrial operations was pioneered in the SOLID POWER(copyright) brand technology claimed in Fernholz et al., U.S. Reissue Pat. Nos. 32,762 and 32,818. Additionally, sodium carbonate hydrate cast solid products using substantially hydrated sodium carbonate materials was disclosed in Heile et al., U.S. Pat. Nos. 4,595,520 and 4,680,134. In recent years attention has been directed to producing highly effective detergent materials from less caustic materials such as soda ash also known as sodium carbonate. Early work in developing the sodium carbonate based detergents found that sodium carbonate hydrate based materials swelled, (i.e., were dimensionally unstable after solidification). Such swelling can interfere with packaging, dispensing and use. The dimensional instability of the solid materials relates to the unstable nature of various hydrate forms prepared in manufacturing the sodium carbonate solid materials. Early products made from hydrated sodium carbonate typically comprised a one mole hydrate, a seven mole hydrate, a ten mole hydrate or more typically mixtures thereof. After manufacture, upon storage at ambient temperatures, the hydration state of the initial product was found to change. Often this change involved a change from a dense hydrate to a less dense hydrate and resulting in an increase in volume of the block product. This hydrate change was believed to be the cause of the dimensional instability of the block chemicals. Substantial efforts were made to forming a solid comprising a one mole hydrate that was chemically and dimensionally stable. Substantial success was achieved in this research and development project. However, further work was directed to both the chemistry and processes involved in cast solid block manufacture. Detailed experimentation was directed to different compositions that could be used in manufacturing sodium carbonate detergents. Further, significant process studies were initiated to develop improved process parameters in manufacturing solid block detergents.
A variety of investigative programs were initiated to explore the parameters of solid block detergent manufacturing using casting and extrusion technology. The economics, processability, utility and product stability of the solid products were continually investigated to obtain improvements over quality and useful products.
In the past, solid block detergents were solidified using a freezing of a low melting point sodium hydroxide hydrate, by using a thermoplastic organic or inorganic solidifying agent or through other mechanisms. We have found that this solids technology can be extended to materials other than detergent and that an improved solid block functional material can be made using a binding agent that is intentionally prepared in the solidifying mix. The binding agent comprises a carbonate salt, an organic acetate or phosphonate component and water in a binder material we have identified as the E-form hydrate. In the E-form hydrate binder for each mole of organic phosphonate or amino acetate there is about 3 to 10 molar parts of alkali metal carbonate monohydrate and 5 to 15 molar parts of water based on the binder weight. This hydrate has not been formed to date in previous carbonate materials.
In our experimentation with respect to the use of organic phosphonate sequestrants in sodium carbonate solid block detergents, conclusive evidence for the existence of the hydration complex has been found and distinguished form earlier carbonate detergents. The new complex comprises an alkali metal carbonate, an organic phosphonate sequestrant and water. This complex is distinctly different from typical sodium carbonate monohydrate, or higher hydrate forms (Na2CO3.xH2O, wherein x ranges from 1 to 10). In the manufacture of prior art carbonate containing solid block detergent, the most useful solidifying agent comprises sodium carbonate monohydrate. We have found that a solid block detergent can be manufactured comprising sodium carbonate, an organic phosphonate or acetate, less than about 1.3 moles of water per each mole of sodium carbonate and other optional ingredients including nonionic surfactants, defoamers, chlorine sources. Under these conditions, a unique cast solid block functional material is manufactured from a mixture of ingredients having both hydrated sodium carbonate and non-hydrated sodium carbonate. The mixture is formed into a solid block using a hydration complex comprising a portion of the sodium carbonate, the organic phosphonate or acetate sequestrant and water. The majority of water forms carbonate monohydrate within the overall complex. The complex appears to be a substantially amorphous material substantially free of crystalline structure as shown in x-ray crystallographic studies. The material solidified by the complex is in large part, about 10 to 85 wt. %, Na2CO3.H2O (monohydrate). Less than about 25 wt. %, preferably about 0.1 to 15 wt. % anhydrous carbonate.
The E-form hydrate acts as a binder material or binding agent dispersed throughout the solid containing the ingredients that provide the functional material and desired properties. The solid block detergent uses a substantial proportion, sufficient to obtain functional properties, of an active ingredient such as a detergent, a lubricant, a sanitizer, a surfactant, etc. and a hydrated carbonate and non-hydrated carbonate formed into solid in a novel structure using a novel E-form binder material in a novel manufacturing process. The solid integrity of the functional material, comprising anhydrous carbonate and other cleaning compositions, is maintained by the presence of the E-form binding component comprising carbonate, an organic phosphonate or acetate, substantially all water added to the detergent system (an associated fraction of the carbonate forms with the complex). This E-form hydrate binding component is distributed throughout the solid and binds hydrated carbonate and non-hydrated carbonate and other detergent components into a stable solid block detergent.
The alkali metal carbonate is used in a formulation that additionally can include an effective amount of a hardness sequestering agent that both sequesters hardness ions such as calcium, magnesium and manganese but also provides soil removal and suspension properties. The formulations can also contain a surfactant system that, in combination with the sodium carbonate and other components, effectively removes soils at typical use temperatures and concentrations. The block structure can also contain other common additives such as surfactants, builders, thickeners, soil anti-redeposition agents, enzymes, chlorine sources, oxidizing or reducing bleaches, defoamers, rinse aids, dyes, perfumes, etc.
Such block functional materials are preferably substantially free of a component that can compete with the alkali metal carbonate for water of hydration and interfere with solidification. The most common interfering material comprises a second source of alkalinity. The detergent preferably contains less than a solidification interfering amount of the second alkaline source, and can contain less than 5 wt. %, preferably less than 4 wt. %, of common alkalinity sources including either sodium hydroxide or an alkaline sodium silicate wherein the ratio Na2O:SiO2 is about 2:1 to 1:1. While some small proportion sodium hydroxide can be present in the formulation to aid in performance, the presence of a substantial amount of sodium hydroxide can interfere with solidification. Sodium hydroxide preferentially binds water in these formulations and in effect prevents water from participating in the formation of the E-form hydrate binding agent and in solidification of the carbonate. On mole for mole basis, the solid detergent material contains greater than 5 moles of sodium carbonate for each total mole of both sodium hydroxide and sodium silicate.
We have found that a highly effective solid material can be made with little water (i.e. less than 11.5 wt. %, preferably less than 10 wt. % water) based on the block. The solid detergent compositions of Fernholz et al. required depending on composition, a minimum of about 12-15 wt. % of water of hydration for successful processing. The Fernholz solidification process requires water to permit the materials to fluid flow or melt flow sufficiently when processed or heated such that they can be poured into a mold such as a plastic bottle or capsule for solidification. At lesser amounts of water, the material would be too viscous to flow substantially for effective product manufacture. However, the carbonate based materials can be made in extrusion methods with little water. We have found that as the materials are extruded, the water of hydration tends to associate with the phosphonate component and, depending on conditions, a fraction of the anhydrous sodium carbonate used in the manufacture of the materials. If added water associates with other materials such as sodium hydroxide or sodium silicates, insufficient solidification occurs leaving a product resembling slush, paste or mush like a wet concrete. We have found that the total amount of water present in the solid block detergents of the invention is less than about 11 to 12 wt. % water based on the total chemical composition (not including the weight of the container). The preferred solid functional material comprises less than about 1.5, more preferably about 0.9 to 1.3 moles of water per each mole of carbonate. With this in mind for the purpose of this patent application, water of hydration recited in these claims relates primarily to water added to the composition that primarily hydrates and associates with the binder comprising a fraction of the sodium carbonate, the phosphonate and water of hydration. A chemical with water of hydration that is added into the process or products of this invention wherein the hydration remains associated with that chemical (does not dissociate from the chemical and associate with another) is not counted in this description of added water of hydration. A hard dimensionally stable solid detergents will comprise about 5 to 20 wt. %, preferably 10 to 15 wt. % anhydrous carbonate. The balance of the carbonate comprises carbonate monohydrate. Further, some small amount of sodium carbonate monohydrate can be used in the manufacture of the detergent, however, such water of hydration is used in this calculation.
For the purpose of this application the term xe2x80x9csolid blockxe2x80x9d includes extruded pellet materials having a weight of 50 grams up through 250 grams, an extruded solid with a weight of about 100 grams or greater or a solid block detergent having a mass between about 1 and 10 kilograms. These detergents can be used in both laundry and warewashing. Laundry detergents can include surfactants, brighteners, softeners and other compositions not used in warewashing.